Gritters out as Scotland braced for 30C on hottest day of the year

Scotland is expected to have its hottest day of the year later, with temperatures forecast to hit 30C in southern areas.

It will meet the official criteria for a Scottish heatwave, as the UK swelters through some of its hottest June nights on record.

In the Borders, gritters have been deployed to spread sand over the main roads to try and reflect heat and cool the surface.

The Met Office stipulates that temperatures in Scotland must reach 25C for three consecutive days, in the same area, for it to be classified as a heatwave.

A high of 29C was recorded at Dyce in Aberdeen on Tuesday, beating the year's previous high of 28.1C at Floors Castle in the Borders on 25 May.

Scottish Borders Council said the extreme heat was damaging roads in the area, with some reaching 52C.

The B6362 Lauder to Stow road is already closed because of heat damage.

David Robertson, chief executive at Scottish Borders Council, said they were expecting temperatures to reach 31C in Newcastleton and Hawick.

He said: "If you see the gritters, it's not the council being daft, it's us actually trying to protect the road surface.

"We're providing a fine layer of sand to prevent the melting of the tar.

"What we're seeing is ambient road temperatures at the height of the heat up in the 40s, and that causes the tar on the roads to melt."

Meanwhile, Dumfries and Galloway Council has asked residents to "spare a thought for our frontline staff" wearing personal protective equipment in the heat.

Police Scotland issued reminders about water safety and the risk of drowning from "cold water shock".

However, anglers in the south have been warned about the risks to fish when rivers warm up.

The River Tweed Commission (RTC) called for a stop to fishing salmon and trout when water temperatures reach 20C because dissolved oxygen levels puts fish under stress, meaning even careful catch-and-release angling can kill them.

Jamie Stewart, from the River Tweed Commission, said: "Wild Atlantic salmon are already facing unprecedented pressures from climate change, habitat loss and poor marine survival."

BBC Scotland weather presenter Gillian Smart said the heat would peak as southeasterly winds pull in intensely hot, humid air from the continent.

She said: "The highest temperatures will be in central and southern Scotland, where we're likely to see 30 Celsius."

However, she warned of a "thundery breakdown" on Thursday afternoon.

"A weather front to the northwest will interact with the very warm air to produce heavy, thundery showers across the Western Isles, the Northwest Highlands and the Northern Isles.

"These thundery showers will feed southwards across the country, torrential in places, and bringing a risk of hail."

A yellow warning for thunderstorms has been issued for Highlands, Orkney, Moray and Argyll and Bute from 15:00 to 23:59, and for the rest of mainland Scotland from 00:00 to 23:59 on Friday.

The Scottish Environment Protection Agency (Sepa) put six flood alerts in place across the north of Scotland.

The agency said flooding from surface water and small watercourses is possible on Thursday evening and Friday due to heavy rain and thunderstorms in Caithness and Sutherland, Easter Ross and the Great Glen and Orkney.

Findhorn, Nairn, Moray and Speyside, Skye and Lochaber and Wester Ross are also covered by an alert.

Parts of England and Wales have a rare red warning for extreme heat in place and it is expected to be another scorching day for most of Europe.

Temperatures will once again be around 12 to 15C above average across northern Spain, France and into Belgium and the Netherlands.

Dr Vikki Thompson, climate scientist at the University of Edinburgh, said the current heatwave had come in from the tropical Atlantic.

She said the maritime origins of the heat meant it felt much hotter than previous years.

Dr Thompson said the changing climate meant temperatures would continue to increase in future years and adaptations would have to be made to existing infrastructure.

"This year and next year are expected to be particularly hot because of the conditions in the tropical Pacific, it is priming the UK and Europe for more heatwaves this year," she said.

"The infrastructure in Scotland is set up for the climate of the past and not the climate of the present and the future that we are seeing.

"So we will start to see buildings, infrastructure like hospitals and schools, struggling to keep the indoor temperature down to safe levels."